Process for heating wire



March 5, 1935. w CONVERS 1,993,400

PROCESS FOR HEATING WIRE Filed Dec. 31, 1930 Wilbur H. Convens PatentedMar. 5, 1935 UNITED STATES PROCESS FOR HEATING WIRE Wilber H. Convers,Poughkeepsie, N. Y.

Application December 31, 1930, Serial No. 505,704

Claims.

Thisinvention relates to a method for annealing or oxidizing a movingwire during its travel through the device. The invention is es peciallyadaptable for the purpose of annealing 5 wire which is to be insulated.The device for carrying out the method may be installed in a wireinsulating machine, or in other machines where it is desired to annealthe wire at a high rate of speed or at the same rate of speed as that atwhich the wire moves through the machine to which the device isattached. The invention is very suitable for use where it is desirableto clean or prepare the surface of bare wire before it is coated withinsulation. The wire may be only annealed, or, by increasing thetemperature the wire may be oxidized, if desired.

In the usual method now employed for annealing wire, the wire afterbeing wound upon spools is placed in an oven and brought to the requiredheat for annealing, depending upon the size of the wire, etc. In thismethod, any soap or grease compound used in drawing the wire to size,which is wound up with the wire on the spools and annealed in the oven,is deposited upon the surface of the wire. When this soap or compound iscovered with insulating material it will cause spots in the insulation.The same sort of trouble may occur when the wire is passed through aheated pipe or oven, or brought into contact with a flame or otherdirect heating means, either in a suitable chamber or exposed to theair.

Prior annealing methods are slow, require much handling, labor andexpense and another great disadvantage in such methods is that theheated wire will stretch or elongate under any strain while it is hot.This is especially true of the smaller sizes of wire, and thiselongation of the heated portion of the wire makes it hard to feedthrough an automatic winding machine for winding the wire into a coil,etc. In some cases, the diameter of the wire will be reduced by thestretch, thus rendering it unfit for many electrical purposes, due toincreased resistance caused by the reduced diameter of the wire.

With my invention it has been found that a speed of 400 to 600 feet perminute for #40 gauge wire and 200 to 300 feet per minute for #30 gaugewire can be employed without any noticeable stretch or elongation. Withthe degree of the annealing heat under perfect control, speeds higherthan this can be easily reached without objectionable or appreciableelongation of the wire.

One of the objects of my invention is to provide a method for annealingor oxidizing a wire in a continuous manner during the travel of the wirethrough the apparatus.

Another objectof this invention is to provide a method whereby, duringthe heating of the wire, no elongation or stretch of that portion of thewire which is being heated or any other portion of the wire takes placeduring such heat treatment.

Still another object is to provide a method whereby the wire is renderedfree from oil and foreign matter preparatory to its being coated orenameled, when coating or enameling of the wire is desired.

A further object is to provide automatic method so that when heat is tobe applied through an electric current to successive portions of thewire, the electric current is turned on and off by the travel of thewire in such a manner that should the wire become stationary, thecurrent and therefore the heat will be reduced to prevent melting oroverheating of that portion of the wire that is at that instant inposition to be heated and the current is turned on when the travel ofthe wire attains a predetermined rate of speed. Also provision is madewhereby variations in the speed of travel of the wire will not causeappreciable variations in the degree of annealing.

While I show and describe herein an illustrative embodiment of asuitable apparatus for carrying out my invention, it is understood thatmodifications may be employed, such, for example, as a duplication ofparts and change in material and that the device may be enclosed orexposed to the air, and that suitable changes may be made to suit it todifferent sizes of wire or to wire of different material or metals, alsothat by suitable housing the device can be operated so that theannealing takes place in the presence of inert gases, steam, etc.to-prevent tarnish forming on the surface of the wire due to theannealing operation.

My invention comprises a process which may be carried out by certainconstruction and combination of parts illustrated for example in theaccompanying drawing in which Fig. 1 is a side view of the deviceshowing it installed near a wire insulating machine; Fig. 2 is anenlarged side elevation of a portion of the device; Fig. 3 is a frontelevation of the same, shown partly in section; Fig. 4 is a sectionalview, taken on the line A--A of Fig. 3; Fig. 5 is a side elevation ofthe wheel for suspending the wire during the heating; Fig. 6 shows howthe electric current that is supplied to the device may be varied withincertain limits, and in proportion to speed changes in the rate of travelof the wire; Fig. 7 shows a modification by which automatic control ofthe current can be secured.

The device as here illustrated comprises a base 10 of insulatingmaterial, and to which are secured the two uprights 11 and 11' which areformed at their upper ends with aligned bearings 12 and 12' or a singlesupport may be used if desired.

A rotor comprising two sheaves or wheels 13 and 14 formed of a goodelectrical conductor such as brass, are secured together side by side bymeans of bolts or rivets 15 which are insulated therefrom by theinsulating bushings 16 and the Washers 17,while the sheaves 13 and 14are sep mated by a disk 18 of insulating material, in such a manner thata sheave 13 is electrically insulated from the sheave 14.

The sheave 14 is formed with a stud shaft 19 projecting from its outerface and adapted to rotate freely in the bearing 12. The outer end ofthis stud shaft 19 is pointed as shown at 20 and contacts with a flatspring 21, which is secured to the upright 11 by the screw 22. If acentral upright is employed, as mentioned above, the two sheaves may bemounted one on each side thereof, and the spring 21 may be hinged to asuitable base so that by removing the spring from contact with the endof the shaft the wire may be readily placed on or taken from the wheel.

This sheave 14 is also formed on its inner face with a bore 23 extendingpartway therethrough in line with the stud shaft 19. Within this bore 23is mounted a cup-shaped bushing 24, and within this bushing 24 issecured one end of a shaft 25, the other end of which is freelyrotatably mounted in the bearing 12' of the upright 11'. The shaft 25 ispointed at the end as shown at 26 and is in contact with a fiat spring21. The shafts 19 and 25 thus rotate in the bearings 12 and 12 andcontact with the springs 21 and 21'.

The sheave 13 is recessed as at 27. Within the recess 27 are pivoted onpivots 28 two contact arms 29 which are formed with weighted ends 30which, when the sheave 13 is rotated, will by centrifugal force moveoutwardly and bring the arms 29 into contact with the shaft 25 thusestablishing an electrical connection between the sheave 13 and theshaft 25. This connection is broken by the springs 45 when the wheel 13stops its rotation or reaches a sufliciently low speed to enable thesprings 45 to overcome the centrifugal force.

The uprights 11 and 11 are connected by lead wires 32 and 33,respectively, to an electrical transformer 34 or other source of currentwhich in turn is connected to a power line 35 and 36, the amount ofcurrent from which is governed by a rheostat 37 connected in said powerline. Each of the sheaves 13 and 14 thus constitute a terminal of theelectric circuit.

Above the device and at some suitable distance (which may be varied tosuit conditions) is mounted a single sheave or wheel 38 which is freelyrotatable in a bracket 39 which is mounted on a base 39' of insulatingmaterial, so that the wheel 38 is insulated from all other parts of themachine. This sheave may be made of heat resisting or heat insulatingmaterial, such as moulded mica or asbestos material with a proper centerbearing.

The wire 40 to be annealed is carried from a supply spool 41 to thesheave 14, around which it is given approximately one turn, and is thencarried up and around the sheave 38, then down to the sheave 13, aroundit and to the idler wheel 42, to the applier 43 for coating material,the oven 44 and thence to the wheel 46 and take-up spool 47.-

It is understood that the sheave 38 may be located at a predetermined oradjustable distance from the sheaves 13 and 14 depending upon the sizeof the wire to be treated, the length of time required for eachtreatment and the degree of heat applied. In the application ofelectrical heat as herein shown, the electrical current may be of anydesired voltage being controlled by a rheostat and automatic meansapplied to the device. In this particular it may be here stated thatwhile I have shown an automatic switch built into the wheel, that thismay be located in connection with any of the moving parts or otherpulleys or wheels and may be of any suitable construction to open andclose an electrical circuit by the change of speed of travel of thewire.

In the automatic control illustrated in Fig. 6 of the drawing, I haveshown a governor applied to the sheave 42 comprising a ball governor 50similar to that type used in phonographs, etc. so arranged that speedvariations, such as would occur during starting and stopping, will varythe current and thus insure an even annealing, this being accomplishedby a sliding collar 51 mounted on the shaft 52 to which is pivotallysecured one end of the ball arms 50. The collar 51 is formed with agroove 53 within which is placed one end of a pivoted arm 54, the otherend of which forms the arm for the rheostat which is connected in thepower line from the transformer 56, the wires 32 and 33 being carried tothe wheels 13 and 14.

It has been found in practice that sufficient current to cause a properannealing heat to be generated in the wire when traveling is too greatif the speed of travel is reduced and'will tend to fuse the wire. Alsoif the speed of the wire is increased the flow of current must beincreased to anneal properly and it is highly desirable that theannealing temperature be kept at the proper amount at all times.

By having a rheostat or controlling arm 54 operated by the slidingcollar 51, the pivot point of the arm being at 57, the arm can be madeto move over a suitable row of contacts of the rheostat 55 and vary thecurrent applied to the transformer 56, thus any variation in speed ofthe wire 40 traveling over the wheel 42 will vary the current forannealing.

Where no speed variations are encountered in operation, a simplearrangement, as shown in Fig. 7, may be employed. The motor draws thewire 40 and winds it on the spool 47 by the belt 61 and pulley 62. Ihave shown the primary of the transformer 63 and leads 64 to the motor62 connected in parallel to the power line 65 so that as the motor isstarted the drop in voltage across the terminals will drop across thetransformer and as the motor comes up to speed the current will increasealso in proportion. The secondary of transformer 63 is used forannealing and I have found this entirely satisfactory provided acommutator starting type of motor is employed.

The simple centrifugal switch shown in Figs. 3 and 4 will suffice if asmall amount of unannealed wire is not objectionable at the start andstop of the operation.

In the operation of the device, it will be seen that part of the wire 40which travels up from the sheave 14 to the sheave 38 and back to thesheave 13 is always in the electrical circuit between the sheaves 13, 14and acting as a resistance to the current is heated and annealed duringits travel from the sheave 13 to the sheave 14, but that part of thewire 40 leading from the supply spool 41 to the sheave 14 and from thesheave 13 to the idler 42 is cold and as the two sheaves 13 and 14 aresecured together they move in synchronism. Therefore, as the wire 40 ispulled from the sheave 13, the sheave 14 simultaneously turns the sameamount. No elongation strain is exerted on the hot portion of the wire40 between the sheaves 13 and 14, this part of the wire travelingfreely. It is important that just sufficient tension be employed to keepthe wire 40 in good electrical contact with sheaves 13 and 14, therebeing an expansion and contraction on heating and cooling the wire, sothe wire should be slightly free to accommodate this action on thesheaves.

These portions of the wire which are in contact with the sheaves 13 and14 act as contacts for leading the current to that portion of the wirewhich is looped up from the sheaves 13 and 14 to the sheave 38. Due tothe heat conductivity of the sheaves 13 and 14, the wire which is incontact therewith is not heated. That portion of the wire which is beingheated by the electric current may, if desired, be passed through achamber and heated by any other suitable means.

Also the distance between the device and the pulley 38 may be varied asdesired to govern the length of wire being heated and also the devicemay be so arranged that the sheaves 13 and 14 may be mounted on acentral bearing and the springs 21 hinged so that the wire may be placedthereon from the side and not have to be threaded between the uprights11 and 11'. It is also understood that direct current could be usedinstead of alternating, with suitable changes.

I claim:

1. The process of heating a wire which comprises movingsaid wirelongitudinally in contact with seperate electrical terminals wherebyelectric current flows through said wire between said terminals whiletension on said .wire is prevented, the direction of motion of said wirebeing reversed between said electrical terminals.

2. The process of heating a wire which comprises moving said wirelongitudinally in contact with separate electrical terminals wherebyelectric current flows through said wire between said terminals, saidterminals being located side by side and connected to each other bymeans other than said wire and moved at the same rate of speed as saidwire.

3. The process which comprises moving a wire longitudinally and heatingportions thereof in successiomin the shape of a U in accordance with thespeed of movement of said wire and avoiding tension on the portions ofthe wire as they are being heated.

4. The process which comprises moving a wire longitudinally and heatingportions thereof in succession in the shape of a U, avoiding tension onthe portions of the wire as they are being heat-- ed, and cooling saidwire at the hot end of said heated portions.

5. The process which comprises moving a wire longitudinally and heatingportions thereof in succession, relieving tension on the portions of thewire as they are being heated,- and cutting off the heat when the speedoi. movement of said wire becomes less than a predetermined amount.

WILBER H. CONVERS.

